Restricted slit silicon solar cells have been steadily used by the Army since the early 1970's to indicate the solar attitude and the roll rate of a projectile. Earlier versions of this technology may have originated in England in the early 1950's. These prior art slit restriction/cell designs have problems in both field-of-view and linear response specifications. In addition, most designs appeared prohibitively voluminous in practice. Our design provides increased sensitivity, linear response, and reduced size constraints required for advanced munitions concepts.
One prior art publication dealing with this technology is SIR No. H746 published in February 1990 entitled "Solar Reference Flight Roll Position Sensor". The device disclosed in this publication is a sensor that uses the sun as a roll position reference. The sunlight passes through an opaque screen, which has an aperture, and the sunlight illuminates a photo detector. The electric pulses that are generated are processed to form a discriminant that is a function of roll position. Roll rate of the flight vehicle is determined by measuring the rate of change of the roll position. The disclosed design, however, is complicated, large in design, not g-hardened, and designed for low roll rate applications of space vehicles.